1. Field of the Invention
The present invention is directed generally to data network communication.
2. Description of the Related Art
Wi-Fi is used to identify a technology directed to wireless local area networks (WLAN) based on the IEEE 802.11 specifications (including 802.11, 802.11a, 802.11b, 802.11g). The technology can be used for mobile computing devices, such as laptops, in LANs, and other device connectivity. Both the 802.11 family of networking protocols and the 802.3 family of networking protocols involves an area of networking sometimes referred to as infrastructure networking that is related to networking other than peer-to-peer networking.
802.11 has a maximum bandwidth of 2 Mbps, which can be too small for many applications. 802.11b supports bandwidth up to 11 Mbps, which is comparable to traditional IEEE 802.3 and other Ethernet versions. 802.11a supports bandwidth up to 54 Mbps and signals in a regulated frequency spectrum around 5 GHz. Compared with 802.11b, 802.11a is faster, supports more simultaneous users, and uses regulated frequencies to prevent signal interference from other devices. 802.11a has a shorter range signal that is more easily obstructed than 802.11b. 802.11b uses the same radio signaling frequency as the original 802.11 standard whereas 802.11a uses higher frequency. 802.11g has bandwidth up to 54 Mbps with a comparably large number of simultaneous users, uses the 2.4 Ghz frequency for greater range and relatively high resistance to obstruction, and is backwards compatible with 802.11b. Unfortunately, since 802.11g uses the same unregulated frequency range as 802.11b it can also experience interference with appliances that has caused problem for 802.11b.
As defined by the U.S. Federal Communications Commission (FCC), ultra-wideband (UWB) in general refers to a radio technology having bandwidth larger than 500 MHz or 25% of the center frequency. To its credit, UWB is able to share spectrum between users. In 2002, the FCC authorizes unlicensed use of UWB in a portion of the radio spectrum between 3.1 GHz and 10.6 GHz. Consequently, various communication technologies can share this portion of the radio spectrum due also to the inherent ability of UWB to share spectrum between devices. Some of these technologies can range from radar, imaging systems, and short range and long range data communication.
The short duration of UWB pulses allows for very high data rates and has allowed UWB technology to emerge in the area of wireless personal area network (WPAN) transmission systems with bandwidths of at least 500 MHz or a signal occupying an instantaneous fractional bandwidth (BW) of at least 20%. The WPAN technology utilizes point-to-point or peer-to-peer communication directly between two devices as opposed to other types of network traffic found on local area networks (LAN). UWB technology used for WPANs enables the transmission of very high data rates, such as up to 480 Mbps, at a range less than 10 meters, which is a range suitable for a WPAN. UWB also has the potential for upward scalability (up to 1 Gbps) and the throughput capability of multiple streams of simultaneous high definition video/multimedia/data payload.
The following key application areas for UWB technology have been identified in the UWB community: 1. wireless video connection between set top boxes and/or digital video disk (DVD) players and display devices such as monitors and projectors; 2. multiple high definition television (HDTV) video stream transmission from server to multiple clients/terminals; 3. synchronized transmission of HDTV video streams from video server to wide screen or multi-screen display systems; 4. computing equipment interconnection with universal serial bus (USB)-over-UWB (wireless USB); and 5. consumer equipment interconnection using IEEE1394-over-UWB (wireless IEEE1394) and/or co-existent wireless USB.
Standards for implementing WPANs using UWB radio transceivers are defined by the WiMedia Alliance and address issues such as data sharing and transmission within WPANs. The UWB/WiMedia conventional standards are directed toward peer-to-peer data sharing or transmission with WPANs. Pursuant to these standards, WPAN systems have been developed to provide methods of adaptation to standard protocol layers such as a peer-to-peer wireless universal serial bus (WUSB) such with a conventional UWB WUSB device 10 shown in FIG. 1. The UWB WUSB device 10 has a USB application layer 12 that passes data through a USB protocol adaptation layer (PAL) 14 and furthermore through a WiMedia WPAN UWB MAC layer 16 to transmit the data through a UWB physical layer 18 in the assigned UWB radio frequency spectrum.
The USB PAL 14 is used to enable communication between conventional USB application layer 12 that was originally designed for use with other forms of MACs for other physical media such as USB cabling. The USB PAL 14 packages data and instructions from the USB application layer 12 to conform with the WiMedia WPAN UWB MAC layer 16.
In the WiMedia WPAN UWB MAC layer 16, timing between UWB devices is based on super-frame time periods. Features of the WiMedia WPAN UWB MAC layer 16 include decentralized device operations and a combined use of a carrier sense multiple access (CSMA) protocol portion and time division multiple access (TDMA) protocol portion. A beacon portion of each super-frame time period serves as the initial timing portion of the super-frame period in which the UWB devices of a WPAN have autonomous access to the WPAN and identify themselves with individualized beacons. Through the TDMA protocol portion, reservations are announced during the beacon portion and a distributed reservation protocol (DRP) is used for isochronous data or other time-critical data. In turn, the CSMA protocol portion is used as the medium access method with prioritized contention access (PCA). Furthermore, each super-frame time period includes 256 medium access slots (MAS) with the WiMedia WPAN UWB MAC layer 16 providing security and encryption to prevent unauthorized access.
One implementation of the UWB physical layer 18 has a total frequency allocation of 3.1 GHz to 10.6 GHz, 14 bands each with a band width of 528 MHz. It uses 128 point orthogonal frequency division multiplexing (OFDM) with 100 data, ten guard, 12 pilot and six null subcarriers. Mandatory data rates of 53.3, 106.7 and 200 Mb/s are specified while 80, 160, 320, 400 and 480 Mb/s are optional. A total of five band groups are defined with group one being mandatory. There are four groups of three bands each and one group of two bands, yielding a total of 30 channels.
Other standard protocol layers, namely TCP and IP protocol layers, have been adopted for use with UWB for other peer-to-peer communication between devices so enabled such as shown in FIG. 2 with a conventional peer IP device 20 having TCP/IP layers 22. The TCP/IP layers 22 pass data through a WiNet peer IP PAL 24 and furthermore through the WiMedia WPAN UWB MAC layer 16 to transmit the data through the UWB physical layer 18. The WiNet peer IP PAL 24 generates a WiNet frame 30 having a WiNet portion 32 to contain among other things peer-to-peer networking information such as peer-to-peer addressing, a destination address portion 34, a source address 36, and a data portion 38. The WiNet peer IP PAL 24 places peer-to-peer information 40 that is above the IP layer, such as found in a peer-to-peer implementation of TCP into the data portion 38 of the WiNet Frame 30. The WiNet peer IP PAL 24 places a WiNet destination IP address 42 and a WiNet source IP address 44 into the destination address portion 34 and the source address portion 36. The WiNet peer IP PAL 24 passes the WiNet frame 30 on to the WiMedia WPAN UWB MAC 16, which then processes the WiNet frame to be placed into a UWB super-frame 50 as positioned between the two beacon slots 52 of the super-frame to occupy a slot 54.
Unfortunately, the high bandwidth of UWB technology remains dedicated to peer-to-peer communication being limited to the relatively small areas of individual personal area networks.